Configure OIDC end_session_endpoint

[MarcialRosales]

Proposed Changes

Implements feature request #11103

Doc's PR -> rabbitmq/rabbitmq-website#1925

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[michaelklishin]

This Dialyzer failure looks legit

  Proceeding with analysis...
oauth2_client.erl:22:29: The call oauth2_client:get_oauth_provider
         (OAuth2ProviderId :: binary(),
          ['token_endpoint']) will never return since the success typing is 
         ([any()],
          any()) -> 
          {'error', _} |
          {'ok',
           #oauth_provider{issuer ::
                               'none' | 'undefined' |
                               binary() |
                               maybe_improper_list(binary() |
                                                   maybe_improper_list(any(),
                                                                       binary() |
                                                                       []) |
                                                   byte(),
                                                   binary() | []),
                           token_endpoint ::
                               'none' | 'undefined' |
                               binary() |
                               maybe_improper_list(binary() |
                                                   maybe_improper_list(any(),
                                                                       binary() |
                                                                       []) |
                                                   byte(),
                                                   binary() | []),
                           authorization_endpoint ::
                               'none' | 'undefined' |
                               binary() |
                               maybe_improper_list(binary() |
                                                   maybe_improper_list(any(),
                                                                       binary() |
                                                                       []) |
                                                   byte(),
                                                   binary() | []),
                           end_session_endpoint ::
                               'none' | 'undefined' |
                               binary() |
                               maybe_improper_list(binary() |
                                                   maybe_improper_list(any(),
                                                                       binary() |
                                                                       []) |
                                                   byte(),
                                                   binary() | []),
                           jwks_uri ::
                               'none' | 'undefined' |
                               binary() |
                               maybe_improper_list(binary() |
                                                   maybe_improper_list(any(),
                                                                       binary() |
                                                                       []) |
                                                   byte(),
                                                   binary() | []),
                           ssl_options :: 'undefined' | [any()]}} and the contract is 
          ([any()], boolean()) ->
             {'ok', oauth_provider()} | {'error', any()}
 done in 0m0.53s
done (warnings were emitted)

oauth2_client:get_oauth_provider/2 expects a list according to its type spec and oauth2_client.erl:22 calls it with a single value as far as I can tell.